What do you do with your books when you finish reading them? Or your video games, DVDs, or CDs that you're tired of? Don't make a run to the used book or music store, sell what you can for pennies, and take the rest to Goodwill. Wouldn't be great if you could extract more value from these items without the hassle of selling them on eBay or at a garage sale?

Swaptree allows people to trade media - books, music, DVDs and videogames - directly with other users users without the use of cash. Any media can be swapped for any other kind of media. So you can trade the book you just finished reading for a DVD, or whatever. The service is free but users are responsible for their own shipping charges.

Unlike existing trading systems, Swaptree does not use an internal economy of points or credits. In other services, you earn credits for shipping goods into the system, which you can then spend on acquiring other users' used goods. The benefit of this virtual currency is that any item sale contributes to your capability to buy any other item anywhere in the system. That's the great thing about money--it's flexible.

In Swaptree, there are no credits. All trades are person to person. You list what you want to trade and what you want to get, and whenever there's a match, the system will enable you to do a direct one-to-one trade with a person who has something you want and wants something you have. It will also enable three- and four-way trades, coordinating the shipment of multiple items between its members so that everybody unloads what they don't want and gets what they do, even if there's no pair of users with precisely correlating wishes.

The website makes it easy to conduct trades. All you have to do is enter the UPC or ISBN code on the back of the media and Swaptree fills in the details. All you have to do is enter the item you want to trade, and you’ll be presented with items you can receive in trade. Their algorithm will also set up trades with up to 4 people, increasing the likelihood that you’ll see something you like.

In addition to maintaining a list of items that a user wants to trade, they simply build a long list of items they want to own as well. This list can be created by clicking on items on the website and have them included on your “wish list”. If there is a match between an item that you have and an item that you want, Swaptree suggests that a trade occur to both parties. If both accept, the trade is confirmed.